OpenStreetMap

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Recent diary entries

Request for open street map of karu nasarawa nigeria

Posted by Andrew Dangiwa on 28 March 2017 in English (English)

Entire Local government

Location: Karu International market, Kubewa, Karu, Nasarawa, Nigeria

Are maproulette challenges undiscussed mechanical edits?

Posted by imagico on 28 March 2017 in English (English)

Maproulette challenges have become fairly popular recently, especially due to Jochen's Area fixing project. But it seems this has gotten out of hand now and creates serious damage to the OpenStreetMap project.

In general this kind of tool is prone to inviting mechanical work. But with the recent Island and Shoreline Alignment challenge this really gets over the top. I first saw this when various edits turned up in remote areas of the world by various mappers in very high frequency editing islands in changing locations far apart within minutes, often without factual basis and often factually incorrect.

This challenge does everything wrong that can be done wrong with a fixing effort:

  • there are no useful instructions to the mapper what to do and what problems to consider. It only says: ''Align the highlighted island to match imagery''.
  • there is no documentation who created this task and how the allegedly misaligned islands are detected.
  • and most importantly: the task covers areas where the global images routinely available offer no basis for improving the existing data.

Task: Align the highlighted island to match imagery Task: Align the highlighted island to match imagery (link)

Especially the last point is a big practical issue now since the edits made through this challenge misalign and worsen a lot of data in OSM. I commented on two most obvious cases where Bing offers no image at all but mappers none the less blindly followed the task to Align the highlighted island to match none-existing imagery with obvious results. But even in areas where Bing offers low resolution images these hardly ever allow improving existing data. These images in Bing are mostly from >15 years old L1G Landsat 7 images which have positional errors of sometimes more than 100m and rarely allow substantially improving existing mapping. In most cases attempts to do so made within the challenge worsen data which has often been mapped from either better data or with better alignment of the images.

With edits like this the island in question is not necessarily less accurate than before - the mapping before was done based on - if at all - only slightly better aligned images. But it is no improvement since it is likely not more accurate than before in absolute terms and is definitely less accurate relative to the surrounding features.

Yes, these images show a lot of potential to improve mapping here Yes, these images show a lot of potential to improve mapping here

The least that needs to be done here is

  • stop the challenge as it is now
  • limit it to areas where high resolution images are available in common sources
  • create clear instructions for the mapper advising them to properly check image alignment and find the best quality sources in the area and check if existing mapping might already be of better quality based on other sources. This is not possible to do within a few minutes if you pick random locations all around the world of course.

Of course not all edits made within these challenges even in areas where Bing is poor are bad, there are also some experienced mappers participating here who know how to properly assess and select images.

If whoever created this challenge seriously wants to improve mapping in remote areas the most basic, most productive and most obvious way would be to provide better quality images.

And in general i think we need to put a review regime on organized mapping efforts like maproulette challenges requiring at least basic documentation of the process used to generate the task and ensuring there are proper instructions for the mappers and no nonsense tasks on a larger scale. A lot of thoughtful tasks have been offered in maproulette in the past but apparently this is not something that can be relied upon to be ensured without a QA process for the QA process...

POI Completeness

Posted by Glassman on 27 March 2017 in English (English)

ramyaragupathy asked me recently how well I thought Seattle was mapped. One of the areas was very broad, POI's which makes answering the question very difficult. Thinking about the question lead to what outside data source could we compare to OSM to get a sense of completeness.

I stumbled across the King County Health Department Restaurant Inspections. Every restaurant inspection, going back many years, is available in the counties open data repository.

The data needed some massaging, food inspectors seem to think that they shouldn't limit themselves to just restaurants but any business that serves food, including schools, company cafeterias, the fried chicken (ugh) found in mini marts and food trucks. After removing businesses that didn't match amenity=fast_food or restaurant or cafe it appears that OSM has 1,714 food service businesses vs. 3,680 inspected by the county or 47%, slightly less than half.

The actual results are most likely somewhere near 47% but OSM many have some closed businesses and the county's list may be over stated (I may have keep businesses that should have been excluded.)

That brings up the question - what to do with all of the county's data. It's definitely not something I'd like to see imported, but it would be nice to see better coverage. What are your recommendations?

Clifford

Maproulette Newsletter - March 2017

Posted by mvexel on 27 March 2017 in English (English)

Here is the latest from the MapRoulette world! If you want to get this newsletter in your mailbox, you can sign up here!

featured MapRoulette was featured in the JOSM message of the day!

MapRoulette has seen a lot of activity in the past month! A total of 407 mappers have logged on and fixed more than 32000 tasks. That is really cool.

New and notable challenges

Also, lots of new challenges! 539 to be precise created in the last month. I know that challenges can still be hard to discover (working on that, I would welcome ideas and help there!) so I want to just manually highlight some challenges that look interesting. If you want your challenge highlighted in this newsletter, please write to maproulette@maproulette.org!

shorelinesvsreality

The latest from Github

How to: Task Instructions

Perhaps you have seen that the task instructions do not always fit in the panel.

nofit

That is annoying because it can be unclear what you should do. Usually this is caused by hyperlinks that are too long and can't be broken up. If you are a Challenge creator, you can avoid this by using markdown to wrap the hyperlink. Instead of using the raw link in your instruction (https://long-long-url.org), use this: [description](https://long-long-url.org)and it will be displayed like this: description.

Help Wanted: Challenge Administrators

With so many new challenges coming in, it would be great if a few of you would volunteer to help with Challenge maintenance. That means looking at new Challenges that users create to see if they make sense, and helping the Challenge creators to improve them if needed. If you are interested in helping with this, email maproulette@maproulette.org!

That's it for this month. Please write in if you have suggestions for this newsletter. Happy mapping!

Searching for the Source of Ouse Dyke

Posted by alexkemp on 27 March 2017 in English (English)

Oh yes! History is full of the names of famous Explorers, searching for the source…

…and so, in honour of these & other, similar noble exploits, on Sunday 26 March 2017 your mapper selflessly set forth into the wildlands of the heights of Gedling Country Park to discover the source of …, erm, Ouse Dyke (I do wish that they could have given it a bit of a more romantic name) and …, erm, got my Clarks muddy. So yes, no trouble nor expense shared to nobly & selflessly bring the wonders of Gedling slag heap to your door.

A short length of Ouse Dyke was marked up in those heights on the Nottingham City Adopted Highways Register, and I'd noticed obvious signs of a bridge across Lambley Lane that should contain Ouse Dyke (although now culverted), plus manhole covers for a culvert North-South across Lambley Lane Recreation Ground, so I was confident of a result.

Here are some highlights of that mapping session, using my new-new smartphone for the first time:–

A northern basin (mapping), fed by culverts & natural drainage from the surrounding hills. As best as I can tell, this is NOT a source for Ouse Dyke, although goodness knows what Severn Trent does if the rainfall is too large:–

Gedling Country Park, northern basin

As you can tell by the lack of fencing, Gedling Council is rather Spartan towards it's children rather than treating them as soft Athenians. That also shows in the way that it only warns you of the drop as you are about to fall, and the lack of a lifebuoy in the Lifebuoy holder.

South of the Northern Basin is (surprise surprise) a Southern Basin (mapping). This one boasts (at least one) swan & ducks (the northern one only had swimming dogs when I was there):–

Gedling Country Park, southern basin

Having become an expert on Flood Lagoons, these two look like Retention lagoons, in that there are zero pumping mechanisms in sight. I assume that any excess will have to drain to the west into the trees (to the North, East & South are high-parts formed from spoil dumped from the now-closed Gedling Colliery). Some of the efforts to safely drain & re-green the slag-heap show in the next few pictures, each taken from further to the south & east:–

slag-heap culverts, looking northslag-heap culverts, looking southconcrete slag-heap culverts, looking north

At the time I thought that I had hit Ouse Dyke pay-dirt but, seeing the pictures in the context of the map, it was clear that these all drained into the Southern Basin, so maybe not.

The amount of efforts taken here by Severn Trent are extreme, and it was viscerally clear to me that Water Engineers such as those employed by ST have taken on-board the horrible lessons of Aberfan from 1966 (a coal slag-heap in Wales, built upon a stream, which washed an avalanche of muck down the hill and into Pantglas Junior School directly below it, killing 116 children and 28 adults).

The following stream seems most likely to directly be the modern source of Ouse Dyke (I have put it on the map but it is hidden by trees & needs proper tracking). It is south & below the southern Basin and is heading south-east. It is a handful of metres north-east of the Information Map (mapping), which itself is a few metres north of where the abandoned mineral railway, older hiking track and proposed Gedling Access Road all pass:–

Ouse Dyke source?

Addendum 1: I've changed the mapping from waterway=stream to waterway=ditch, as we are dealing with an artificial drain created by Severn Trent rather than a natural stream leaping merrily from rock to rock.
Addendum 2: the following note has been added to the mineral railway:

2017-Mar: Google Earth shows one (sometimes two) rail-tracks on the land; they must have added them afterwards, as none exist.

In the North Recreation Ground there are two manhole-covers (only the second is pictured below):–

Ouse Dyke manhole-cover

It is perfectly reasonable to say that a culvert passes between them and, seeing as continuing the line of that culvert towards town, that there is a bridge that crosses Lambley Lane (below) (although today with a non-existent stream flowing through it) I also believe that it is perfectly reasonable to assume that the culvert passes through that bridge across to the other side:–

Ouse Dyke bridge on Lambley Lane

Further mapping on the continuing line of that culvert, plus it's appearance as a stream, will have to wait until I actually map that area (coming soon). However, there is a final oddity within the Recreation Ground…

The photo below was taken on November 27, 2016 and is of a stream that rises within what is now Mapperley Golf Course and exits into a culvert operated by Severn Trent Water at the southern-most point of the Course:–

Ouse Dyke beginning in Mapperley Golf Course

That culvert was originally found within a NPE map & transferred onto OSM many years ago. After someone raised doubts about it, I spent all the months between November & now trying to find someone to speak about it, but no-one answered my knocks on their door. It finished on NPE within the Recreation Area, close to the southern Manhole cover. I think that it merges with that culvert (but have not moved it).

The final item is to make note of my re-mapping of a "historic:waterway"="stream" which is on the map but never appears (due to missing tags). Originally it met with & combined with the NPE culvert, and it looks like it is supposed to come from the drain further to the north. I've:

  • disconnected it from the NPE Culvert
  • connected it with the northern man-hole instead
  • have given it culvert tags instead of stream tags
    (there isn't a stream that wanders across all the football pitches)

And that is the end of the search for the source of Ouse Dyke. It seems very much like it is a combo of a stream coming down from (what is now) Gedling Country Park and a small stream that originates within (what is now) Mapperley Golf Course.

Location: Arnold and Carlton, Gedling, Nottinghamshire, East Midlands, England, United Kingdom

Olivio Di Biasio

Posted by Olivio Di Biasio on 27 March 2017 in English (English)

Olivio Di Biasio owner of Carrelage Mozaik which is licensed tilling company based in Greater Montreal Area, Canada. Olivio Di Biasioh having 25 years of experience in the field of tiling and providing their unmatched services in and around the area. They are very experienced and providing work all according to client’s requirements. They are providing work from simple to detail-oriented projects with new technology. They are always focusing on using new technology to provide best work to their client. Olivio Di Biasio is very nice, down to earth, and simple person who is always ready to help people.

Protecting the map against Pokemon Go mappers

Posted by PlaneMad on 27 March 2017 in English (English)

The Pokemon Go mappers can strike anywhere, converting buildings into parks or pools of water. Check any changeset with 'Pokemon' in the changeset comment using osmcha.

Views from Gedling Country

Posted by alexkemp on 26 March 2017 in English (English)

My current mapping is on the eastern edge of Gedling. Gedling prides itself as a village, with an Anglican church that was established in 678 A.D. (the current church is a youngster at 1089 A.D.). Today, someone that lives in a bungalow at Field Close at the rear of the church was proudly pointing out to me the Peregrines that lodge in the niches of the spire. The tower is 90 feet high (27.4m) and the spire is yet another 90 feet, so that gives those dive-bombers an unrivalled perch for launching their attacks.

In spite of it's history, Gedling is now more or less just another suburb of Nottingham. It does, however, skirt the countryside and I'm mapping on the edge of that country, so here are some views.

Want any Horse Sh.., er, Manure?

Glebe Farm is an abandoned stables just outside of the residential spread that has crept up Lambley Lane. It has suffered decades of blight due to development, the latest of which (“Gedling Access Road”, or “GAR”) looks like it may go ahead. There were some horses in the East fields, a Detectorist scanning the West fields, and below is Milo the dog, an energetic bull terrier that belongs to the lady that looks after the horses. Milo leapt up at me & introduced my buff-coloured trousers to the farm speciality (there are twin piles of the stuff in abundance near the gate if your garden needs any).

Glebe Farm stables + Milo the dog

Evidence of Strip Farming in Glebe Farm West Fields

A chap in Jessop Lane (the road formerly called “Hanging Lane”, since those due to be legally despatched were marched up that lane to the gallows up on top of the hill) pointed out that Glebe Farm’s West fields still show signs of the way that they were used hundreds of years ago as common-land strip-field farming. That evidence is all due to be lost under tarmac if the proposed developments go ahead (it all looks full-steam at the moment), but can currently still be seen in either Google Earth or Bing (the Bing-tile below has a capture date of 2011/10/1-2012/3/26; the construction at bottom right is a Western Power sub-station):

strip farm signs in Glebe Farm, Gedling

The Road Less Well Travelled

The next sight may not seem much, and indeed was shot only so that the embedded GPS in the photo could locate the position of the 30/40 mph signs, but it is, for me, also a classic view of English country-roads:–

an English country road

Doggedly Well Ensconced

This next view of an English country house is also a side-product of the GAR & development, as the couple of acres of grass & trees between this house & Lambley Lane is now owned by the local Council & no building takes place until the future reveals itself:–

an English country house

Location: Arnold and Carlton, Gedling, Nottinghamshire, East Midlands, England, United Kingdom

What's cooking at Mapbox this week

Posted by kepta on 25 March 2017 in English (English)

As a part of our data transparency efforts at Mapbox. We created osm-edit-report which helps anyone visualize our teams contribution to OSM.

Just to give a measure, the data team added 0.3 Million objects, 0.2 Million tags, and 3 thousand changesets last week.

This is how the numbers look:

objects-created

Since this data is so huge to grasp at one go, we also have filters which help trim down data and focus on a particular group.

  • Filter by users.

Filter-user

  • Filter by tags

filter-tags

  • Filter by BBox

filter-bbox

The user table showcases all edits made by each user over the course of a week. The saturated blue boxes help emphasize huge edits and the chevrons compare today's edits with the weekly average. table

Overall this tool helps us benchmark our mapping efforts and visualize out priority areas. Please don't forget to share your views on how to make our mapping efforts more transparent.

Link: https://mapbox.com/osm-edit-report

Potlatch 2.5

Posted by Richard on 25 March 2017 in English (English)

A new version of Potlatch 2 with several improvements and bugfixes:

  • 'New-style' multipolygons are supported, where the tags are placed on the relation rather than the outer way. When you edit such a multipolygon, look at the bottom of the tag editor; you'll see that it's displaying the relation tags rather than the way. If you do want to change the tags on the way, you can choose that from the little dropdown menu there.
  • Pop-up dialogue boxes are now generally resizable.
  • In the Advanced tag view, long tag values now wrap onto multiple lines.
  • The background menu is now usable on smaller screens.
  • A 'Clear all' button on the Bookmarks menu.
  • Shift-drag to zoom into a particular area; shift-click + or - to zoom three levels at a time; and you can now zoom out beyond zoom level 14, in which case no data will be displayed or loaded.
  • Shift-< and > jump 10 nodes at a time along a way.
  • Code now compiles with Apache Flex as well as with (older) Adobe Flex.
  • Plus a bunch of other small fixes.

Potlatch 2 is somewhere between 'active development' and 'maintenance mode': there's no massive new features that I'm planning, but I intend to keep making small improvements to it along these lines, plus extra features as and when I'm doing some mapping and figure out a way to make it easier or quicker to use. OSM is lucky to have such an excellent default editor in iD, which gives P2 the freedom to develop as an efficient and comfortable editor for those who like its way of doing things.

Some vandalism

Posted by FrikanRW on 24 March 2017 in English (English)

Vandalism on UP campus

After checking some data of our campus I spot odd additions to the campus map. a User edited some information regarding the name and added some shops that did not exist. I contacted them and asked to revert changes made. Will monitor and follow the steps to correct data if not corrected.

Location: Tshwane Ward 56, Pretoria, City of Tshwane Metropolitan Municipality, Gauteng, RSA

My Manifesto for HOT Board Member Position

Posted by aHaSaN on 23 March 2017 in English (English)

“Love and Compassion are necessities, not luxuries. Without them humanity cannot survive”. - Dalai Lama

Hello, voting members! I am Ahasan, I belong to the coastal district Khulna of Bangladesh. I truly believe in humanity and continuously strive and work towards humanity because my motto in life is ‘if you want to leave a mark in the world, work for the humanity’. This ideology motivated me to expand OpenStreetMap in Bangladesh to make open geospatial data for all and to create OpenStreetMap Bangladesh (OSMBD) community and then work for Humanitarian Open Street Map (HOTOSM). I am truly honored to be nominated by Pete Masters in the global arena of HOTOSM. I express my heartfelt gratitude towards him for believing in me.

Who am I?

  • I am a Remote Sensing and Geographic Information System graduate from Asian University of Technology (AIT), Thailand.
  • I am also a graduate in Environmental Science from Khulna University, Bangladesh.
  • Diploma in Climate Change Vulnerability and Humanitarian Responses at Jointly University of Hawaii-USA, United Nations University, Keio & Okayama University-Japan, National university of Samoa and Asian Institute of Technology-Thailand.

Currently, I am working as a Geospatial data consultant in Global Facility for Disaster Reduction and Recovery (GFDRR) unit which is a global partnership that helps developing countries better understand and reduce their vulnerability to natural hazards and climate change. GIS and Remote sensing is my passion and working with it nationally and internationally for past 12 years. During my Master’s degree in Asian Institute of Technology (AIT) Thailand, I got involved with Open Source GIS. After coming back to my motherland – Bangladesh; GFDRR’s collaborative open city project gave me the chance to work actively with OpenStreetMap. From then on I fell in love with OSM and HOTOSM and till date, I am working passionately for both the communities. Bangladesh didn’t have much knowledge of OSM before 2013. As a GIS specialist and supporter of free and open source projects, I realized the huge potential of OSM in developing Bangladesh, with regular disaster threat and top listed country for climate impacts. I got introduced with Humanitarian Open Street Map Team (HOT) through Jeff Hack and Robert Soden. Later I have worked with Ryan Somerville, Jorieke vyncke, Pete Masters, Dale Kunce, Daniel Joseph, Taichi Furuhashi, Chad Belevins, Patricia Solis and the SOTMUS 2015 gave me the chance to meet most of the legends of OSM/HOTOSM. If anyone asks me why I love OSM/HOT then my response will be, the location data should be open for any emergency, research and for the local community what I felt always during emergency response and in my academic life. I found, to be involved with HOT is a noble work what will serve the community for a long time with a very minimum effort. Therefore I started to disseminate this knowledge among people, building a strong OSM community involving academia, government and non government organizations, youth communities, youth entrepreneurs and the local level low tech community. I voluntarily facilitated more than 35 OSM training and coordinated many more mapping parties in Bangladesh. People hire me for conventional GIS mapping, I introduce OpenStreetMapping that’s how OSM is spreading among the agencies here. I write regularly about opendata and OSM in my personal blog(www.ahasanulhoque.com/category/blog/)

Currently, along with like minded people of our community took decision to create OSM foundation officially to launch more events through agencies and academia. Simultaneously I am campaigning to create more use cases for the OSM data uploaded so far since "Data have no meaning if there is no use". We shouldn’t wait for disaster to use this data only; therefore we need to use the OSM data in research and innovation.

My vision for HOTOSM:

  • I believe, HOTOSM is not only a non-profit organization but also a global family with open mind members who always works for the only purpose - serving the affected global community.
  • If I get elected as a board member, I will try my level best to provide logical, critical and right judgmental decisions for HOTOSM and its sustainable growth in future.
  • Ensure that HOT is a transparent organization for its members who can attend all meetings (Board included) and access all meeting notes, communications and all the Organization documents (specifically finance, admin, projects) ; within of course the respect of privacy.
  • HOTOSM will give me the official identity what will make my stand bold in future venture regarding OSM movement and HOT activation among communities around the world.
  • I ensure that HOTOSM fosters its support to the growth of autonomous local OSM communities (made of individuals, groups, chapters and economic operators) and develop their ability to sustain relations amongst themselves (global-local, South-South, North-South) and with technical communities (OSM, free software and open data) as well as the humanitarian and development actors.
  • My intention is to provide feedback from my knowledge and experiences in many contexts and type of projects, including e.g. budget optimization to systematically encompass support for local emergent OSM communities.
  • As a board member, I will be striving for better future for all HOTOSM communities around the world which meets hopes and resolves concerns.
  • I will be enhancing the networking and collaboration with other HOT members globally and participated in fundraising activates through my all channels.
  • I will be using the many branches that my experience provided me with: strategy, project engineering (design/implementation), reporting, admin/business processes, outreach, networking, advising, grants writing/fundraising and the field-specific technical and organizational skills.
  • Create HOT as an inclusive organization in terms of decision making; specifically in project design tied to subventions, grants, or core funds.
  • Redefine relations and roles between the Board of Directors and Operational staffs (ED and Project Managers).
  • Ensure a shift towards a more active role for the Directors in strategy/planning/design/implementation/monitoring of operations and projects with the ED in charge of running the day to day business. *More importantly, working as HOT Board member will provide me the chance to learn global scale non-profit organizational management.

Thank you very much for nominating me as a Board member of HOT. Vote for the humanity, vote for the deserving candidate. I wish continuous growth of HOT in near future.

Ahasanul Hoque (Candidate for HOTOSM Board Member)

HOT Voting Memeber LinkdIn Twitter OSM Skype: ahasan4u

Location: Nijhum Residential Area, Hazaribagh, Dhaka, Dhaka Division, 1209, Bangladesh

the centre of Berlin

Posted by dieterdreist on 23 March 2017 in English (English)

This is a follow up of my recent diary entry about the centre of Rome and in parts a reply to Warin61's comment to that post.

Generally

I believe the local people usually know where the centre is. They tell you when you ask them. Give it a try, I bet you'll see that you get similar answers.

I would expect this most central spot to be often in front of the townhall (maybe sometimes the cathedral) or the main market square (in traditional towns) or likely both. Maybe the train station can be such a center as well (in more recent towns which developed after the railway was invented).

One criterion could be: where would you go to protest something. If you were to gather together with "all" citizens, where would you go.

Streetsigns aren't useful from my experience. Often the centre is inside the main pedestrian area (typical for Germany, where many historic city centres have been pedestrianized) and it is generally so big that you will get signs in the outskirts indicating "city centre", but when you arrive there will not be a sign stating "this is the city centre", the signs will simply stop indicating a centre when you are in a central area (they might indicate "all directions" now, but that's a different story, maybe to be told another time).

Exceptions

West Berlin

In special cases there could even be several centres, e.g. Berlin (there might be a bit of a difference between big cities and smaller towns). For West-Berliners, the centre was likely Breitscheidplatz (in OSM) and as you can see it is also very close to the former main station of West Berlin, Bahnhof Zoologischer Garten).

East Berlin

For the people in East Berlin it was probably Alexanderplatz (in OSM) with the centre extending also to here (between tower and main town hall. There might be some other opinions because the former centre (castle) was also reclaimed by the officials, naturally (see below). This is Alexanderplatz, you can also see the prominent tower, visible from everywhere in the city. Huge towers are generally issueing a statement of centrality). There's also a station, but it is not important as a train station (it is a very important underground station though, with 3 lines crossing):

Berlin central island

Another central spot and maybe the official centre during the GDR, surely during the German Empire, is the palace (Stadtschloss) (now in reconstruction), (in OSM), in times of the GDR this was the place of the "palace of the republic" (Palast der Republik), at its side there is also the national council.

In this map from 1688 you can see the central island (yellow-green). By that time there were still 2 towns, Berlin (purple) and Cöln (yellow), and this origin is likely a reason that there's some concurrency between Alexanderplatz and the castle. The castle is signed a. Alexanderplatz is in Berlin, while the castle is in Cöln.

The Berlin castle 1900

After tearing down the castle and waiting 20 years (in the meantime they set up a permanent grandstand for their military parades on national holidays), the palace of the republic was errected (after the reunification, the Germans waited again 20 years, until they decided to demolish this "palace" and reconstruct something which imitates the imperial castle's volume and facade).

Tearing down the castle, 1950

Grandstand for parades at the place of the former castle, 1952 (likely not perceived as a centre):

Palast der Republik, 1981:

Closeup of a parade in front of the Palast der Republik, 1978:

Palast der Republik from the inside, 1976

Here's another map to illustrate that this is the centre of the centre (also note how the avenue "Unter den Linden" points straight to the castle (=centre), for many kilometers, and bends right in front of the centre to pass the castle). In red the former castle, gray underneath the palace of the republic, to the north-east Alexanderplatz and its tower):

The current reconstruction called Stadtschloss, (2015). Very visible how Unter den Linden bends for the castle, see it also in a much bigger scale in OSM. This is the main road, leading straight to the castle (current federal road does not completely follow the old road, but I think you can get it) and at the time used by the king to got to his residence in Potsdam. What is now there is in part also result of more recent times: the Nazi plan by Albert Speer).

The OSM crowd currently has set the centre a bit closer to the west, at the crossroads Unter den Linden and Friedrichstraße (in OSM), it's not completely off as this is a very central place (and in the historic parts of Berlin, pre-industrialization), but it isn't a centre where you would go to gather for protest (these would be Pariser Platz in front of Brandenburg Gate and close to the Reichstag, or Alexanderplatz).

I will soon have a look how this node moved around in OSM with the years (and also look for the previous Berlin node that was deleted in 2008).

Location: Scheunenviertel, Mitte, Berlin, 10119, Germany

email

Posted by Nagesh_Blr on 23 March 2017 in English (English)

You can contact me at my email ID nagesh.sa.blr@gmail.com

Montauban, France vandalized

Posted by PlaneMad on 23 March 2017 in English (English)

A new user deleted over a 100 features including the place node in the centre of Montauban, a large town in France.

Just reverted both these changesets:

Caught and reverted in 15 hours! A few tools where one can review changesets from new users apart from the history tab:

Location: Villenouvelle, Issanchou, Montauban, Tarn-et-Garonne, Occitania, 82000, France

RFC: wikidata->osm lookup table

Posted by mcld on 22 March 2017 in English (English)

OpenStreetMap has a wikidata tag which lets us connect OSM objects to their corresponding Wikidata items.

(Technical note: it's a "same as" relationship - i.e. the tag asserts that the two items in different systems refer to the same entity. However, sometimes things in OSM are split into multiple objects; and sometimes one object in OSM actually refers to multiple items in Wikidata. So it's actually a "many-to-many" matching, not "one-to-one": a single OSM object sometimes has multiple semicolon-separated Wikidata identifiers, and multiple OSM objects sometimes have the same Wikidata identifier.)

There are over 600,000 OSM objects with the "wikidata" tag. OK great, job done? I mean, nothing's ever "complete" in these big open-ended crowdsource projects, but if we have more than half a million crosslinks between the systems, that's really good going.

BUT THERE'S A PROBLEM!

Using the tag to jump from OSM to Wikidata works fine. But from Wikidata to OSM? Well, there's no persistent way to link from wkd->osm, simply because OSM's identifiers are impermanent - they're not guaranteed to continue existing, or to continue referring to the same thing. So it's not particularly sensible to store OSM identifiers in Wikidata. Instead, an Overpass lookup is required.

For example, on the OSM Wikidata page I found this friendly Wikidata interface called "Reasonator" - all very nice, but instead of cross-linking immediately to the OSM object, it offers a little "Overpass" link which you can click to do a dynamic lookup.

The effect is that it makes Wikidata->OSM connections indirect, obscured, only-for-those-who-know-they-want-it. If a Wikidata coder says "OK great how do I jump to the item in OSM?" you first have to teach them what Overpass is and how it relates to OSM, then how to use its query language, how many queries a day you're allowed to do on Overpass... bleh.

PROPOSED SOLUTION

Pretty simple proposal, then: a script that produces a Wikidata->OSM lookup table. This could be run as a weekly cron job perhaps (or something monitoring minutely diffs for any changed wikidata tag? dunno) and it could produce a lookup table that is easy for non-OSM users to consume. For example, it could produce a big CSV file like this:

 Q1002133,node/29541385
 Q1002826,node/20919015
 Q1002845,node/241795518
 Q1004173,way/38387732
 Q1004824,node/29164070
 Q1026205,node/410291638,relation/1061137
 Q1005234,relation/2797450
 ...

and a JSON file like this:

 {
 "Q1002133": [["node",29541385]],
 "Q1002826": [["node",20919015]],
 "Q1002845": [["node",241795518]],
 "Q1004173": [["way",38387732]],
 "Q1004824": [["node",29164070]],
 "Q1026205": [["node",410291638], ["relation",1061137]],
 "Q1005234": [["relation",2797450]],
 ...
 }

and then what might be useful could be for these to be published at a stable location, for other programmers to make use of dynamically. The intention is to make it easy for someone with no OSM knowledge and no GIS knowledge to be able to hook OSM into their open data ecosystem.

I wrote a Python script that makes these lookup tables. On my home desktop, it takes about 2 minutes to scan the UK extract; for the whole planet file, it takes a lot longer... 90 minutes! Oof. (The CSV and JSON files produced are 14 MB & 19 MB in size.)

Your thoughts?

New A556 Link Road, Cheshire,UK

Posted by NiborM on 22 March 2017 in English (English)

Congratulations to the people of OpenStreetMap who are the first to show the actual newly completed route and links. Not yet on TomTom or Google maps and don't think about seeing it on OS. Brilliant. Robin

The centre of Rome

Posted by dieterdreist on 22 March 2017 in English (English)

There a very useful feature in JOSM which I just discovered now: when looking at the history diffs of an object and you choose the coordinates tab, you get a map visualizing the geometry in a map.

From time to time people are moving the Rome node.

I found it interesting to see how the position changed by the time. This is the complete position history of the Rome node:

The node creation on 2007-10-15. Back then the local map was empty and a node anywhere near the centre was perfectly fine, but the editor decided after 10 minutes he could do better and already refined to a location close to where the central point commonly is associated with (the Campidoglio). the node creation on 2007-10-15

A further refinement on 2007-10-22. Now the position is perfect (for our means), it indicates the centre of the Campidoglio with the equestrian statue of Marcus Aurelius. further refinement on 2007-10-22

This is the Piazza del Campidoglio with the equestrian statue in the centre, you can also note the concentric pavement structure indicating the centre: Piazza del Campidoglio

Now comes a longer period of people "touching" the node without actually changing it noticably. Take a look at the distance indicator: minor refinement

minor refinement

minor refinement

minor refinement

minor refinement

minor refinement

minor refinement

minor refinement

Until someone comes along and decides in 2011 to relocate the centre close to the Spanish Steps (although this is a famous place, it is not generally considered the "centre point": move to the Spanish Steps

Just one minute later, the same user slightly adjusts the position, but keeps it at the Spanish Steps (Piazza di Spagna): minor refinement

6 months later I relocate the node to the Capitoline Square (Piazza del Campidoglio): relocation to Piazza del Campidoglio

3 years later another user starts readjusting the exact position (maybe in an attempt to optimize the rendering label positions and reduce label omissions): slightly moving away from the centre

Some months later, the node is moved further away from the center to the border of the square: moving to the border

3 months after this, there's a new significant relocation, this time to Piazza Navona (while it is an important place, it is not the "centre"): relocating to Piazza Navona

The same use relocates the node, 2 months later, to the Piazza delle Rotonda (square in front of the Pantheon): relocating to Piazza Navona

That's where we're still right now, but I think I will relocate it to where I believe it belongs and where most of the other mappers also have seen for it the place to be. Well, actually there's another spot which might be brought into discussion as well: it is the place of a column just a stone's throw away on the Roman Forum, close to the temple of Saturn, errected the Emperor Augustus, which is the official start point of the "Vie Consolarie" (main arterial roads, historically until today).

Location: 41,893, 12,483

E. Perry Parkway in Cherry Hills Village

Posted by Terisa on 21 March 2017 in English (English)

Updated with notes on extension of E. Perry Parkway North of Belleview Ave.

Location: East Belleview Avenue, Cherry Ridge, Arapahoe County, Colorado, 80111:80121, United States of America

Harare gets a new name

Posted by PlaneMad on 21 March 2017 in English (English)

Yesterday, Paris became a bicycle shop named France and today the Zimbabwe capital Harare became Hwinidi offices. This time the edit was from iD. The Mapbox data team caught this while reviewing edits on https://osmcha.mapbox.com/ around 13 hours after the edit.

Location: Braeside, Hwindi offices, Harare, Harare, Zimbabwe
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